Pardew said: "I'm astonished, really. It just goes to show you how precarious we are as Premier League managers, and you can't take anything for granted.

"The shock that should be there for the fans and the media should sound something to the owner of that football club because I don't know if that's the ninth manager or whatever it is in so many short years. It's just not fair.

"As far as I am concerned, he has done absolutely nothing wrong. His philosophy was to perhaps change the look of the team, which he has tried to do - that doesn't happen overnight - and he's won two competitions in less than a year, so it's unbelievable.

Wednesday morning's statement from Chelsea revealed they expected to name a replacement for Di Matteo "shortly", with some reports suggesting the new appointment could come in the next 24 hours.

Former Chelsea boss Ruud Gullit believes the haste of Di Matteo's departure ensured that the board had already identified the new man and believes it could be Jose Mourinho.

"I can't believe that Chelsea just sacked him without knowing who is going to be the next one," Gullit told Sky Sports News.

"I will be curious to see what they do in the next couple of days. I can't believe they have just sacked him out of the blue and then they'll be thinking about who is going to be the next one. I don't think so.

"I think they have already in mind who is going to be the next one. It could of course be Mourinho, if it happens, I don't know because it is in the middle of the season."

Gullit believes Mourinho had already been on the club's radar at the end of last season, before Di Matteo's Champions League success prompted them to appoint the Italian full-time.

"I already had a very good feeling that when Robbie won the Champions League that maybe they (the Chelsea board) already had somebody else in the frame to take over," he said.

"I don't think they took any notice of the fact that Robbie could win it.

"That was the reason I believe that they took so long to sign Robbie because they were looking

for other people. In the end they gave it to Robbie.

"I always had the feeling that Mourinho was in the frame all the time - for the simple reason that he signed just after Chelsea won the Champions League.

"He signed his contract with Real Madrid and for me that is no coincidence."

Professional Footballers' Association chief executive Gordon Taylor told Press Association Sport: "I know Roberto well and he is a good man so this is sad news.

"It's also quite incredible that he can be sacked so soon after winning the Champions League and the FA Cup for good measure.

"It just shows that patience now seems a rare commodity at some clubs and that is a shame because the record of other successful clubs shows that stability can breed success."

Liverpool manager Brendan Rodgers, a former member of the Chelsea coaching staff, also had great sympathy for Di Matteo.

"It is disappointing. I have real empathy for him," Rodgers said. "I felt for Robbie because he went in there and did a brilliant job.

"It is incredible you can win the Champions League and a domestic cup competition and find yourself out of a job.

"It is a disappointing day because it really shows the game we are in now as managers. Years ago if you were bottom of the league and maybe hadn't won in 10 games there was probably a likelihood that you might lose your job.

"Now it seems if you are at the top of the league and even winning trophies you lose your job; it is part and parcel of the game now.

"British football was always that little bit more lenient over the years but now seems to have fallen into line with a lot of European ways in relation to managers."

Not everyone disagreed with the decision however, with former Chelsea captain Paul Elliott backing Abramovich's approach.

"Results and performances haven't been to the level of a club of this magnitude," Elliott told BBC Sport. "Abramovich has always been good for Chelsea and will continue to be."

Elliott, who was still at the club when Di Matteo signed as a player in 1996, added: "I think the performance against Juve and the outcome was really the final straw.

"Roberto came in under very difficult circumstances and what he did wonderfully well was stabilise the ship, get the dressing room motivated, got the players playing for him and obviously the success was richly deserved.

"However, Roberto, like every other manager, is in the results business. You can get away with bad results if the team is playing well, but the fact is that he wasn't getting results and the team wasn't playing well."

Despite getting through eight managers in nine years, Chelsea have won three Premier League titles, four FA Cups, two League Cups and the Champions League.

"If you look at the sackings and offset it against the success, they are justified," Elliott said.

"The most important thing is that decisions are made in the best interests of the club and I think the owner and the board are doing that. The results prove they have been the right decisions."